Crop video using ForegroundDetector?

Hello,

I'm using ForegroundDetector to detect a moving object from a fixed camera video. I wondered if there is any way to use this to make a new video with everything but the object removed? I'm using this code from here and it can find the object perfectly, but I would like to produce a new video with everything outside the bounding box made black. Anyone have any ideas?

Thank you :)

videoSource = vision.VideoFileReader('moving.avi','ImageColorSpace','Intensity','VideoOutputDataType','uint8');
detector = vision.ForegroundDetector(...
       'NumTrainingFrames', 50, ... 
       'InitialVariance', 30*30); % initial standard deviation of 30
blob = vision.BlobAnalysis(...
       'CentroidOutputPort', false, 'AreaOutputPort', false, ...
       'BoundingBoxOutputPort', true, ...
       'MinimumBlobAreaSource', 'Property', 'MinimumBlobArea', 250);
shapeInserter = vision.ShapeInserter('BorderColor','White');

videoPlayer = vision.VideoPlayer();
while ~isDone(videoSource)
     frame  = step(videoSource);
     fgMask = step(detector, frame);
     bbox   = step(blob, fgMask);
     out    = step(shapeInserter, frame, bbox); % draw bounding boxes around object
     step(videoPlayer, out); % view results in the video player
end
release(videoPlayer);
release(videoSource);

Answer 1

[Dima Lisin]

You can do that using the foreground mask:

frameWithNoBackground = frame .* fgMask;